Applicant of the present invention has previously proposed in JP-A-10-195494 a method of producing aerated soap which comprises solidifying molten soap containing a large number of bubbles in a cavity of a mold, wherein the step of solidification is carried out in a hermetically closed cavity. The method aims at preventing development of voids or depressions in solidified soap.
According to this production method, outside air not being allowed to enter the cavity, the solidified soap hardly suffers from void or depression development. However, there still is room for further improvement for preventing soap volume reduction due to contraction of aeration gas on cooling molten soap and for preventing resultant shrinkage and/or development of sink marks.